Thanks, Jesse... As it turns out the problem may be a lot simpler. When I applied voltage directly to the motor and it went up and down, it was without the window glass on the regulator. When the window glass was secured to the regulator, and voltage applied directly the window would go down, but either not go up, or struggle to go up (I finally got it all the way up). So, that particular motor is either weak, or the regulator or glass is binding on something. I replaced the 40 amp fuses (they're over $4 each!), and reassembled the door, leaving that motor unplugged until I have more time to mes with it.
I did call a few dealerships, and the motor isn't replaceable on it's own, but has to be replaced with the entire (weak) regulator, to the tune of $210-$230 (parts only).
Long story short: Window is up, it's not going anywhere, everything else worked, and I'm out (so far) around $115.